Control unit for work machine

Abstract

A control unit for a work machine that allows automatically obtaining optimal operability even when the weight of a work arm in the work machine is changed. In a work machine where at least a part of a work arm to be operated by a fluid pressure actuator is provided so as to be replaceable, a control unit for a work machine includes: a pilot-operated control valve that controls the fluid pressure actuator; a proportional solenoid valve that pilot-controls the pilot-operated control valve by a pilot control pressure according to an electrical signal corresponding to a manual operation amount; a measuring means that measures a weight of at least the part of the work arm; and a controller that converts characteristics between the manual operation amount and the pilot control pressure of the proportional solenoid valve to characteristics according to the weight of the work arm measured by the measuring means.

1. A control unit for a work machine comprising:
 in a work machine where at least a part of a work arm to be operated by a fluid pressure actuator is provided so as to be replaceable, a pilot-operated control valve that controls the fluid pressure actuator; 
 a proportional solenoid valve that pilot-controls the pilot-operated control valve by a pilot control pressure according to an electrical signal corresponding to a manual operation amount; 
 a measuring device that measures a weight of at least a part of the work arm, comprising:
 a pressure sensor measuring a holding pressure of the fluid pressure actuator of the work arm; and 
 
 a controller converting characteristics between the manual operation amount and the pilot control pressure of the proportional solenoid valve to characteristics according to the weight of the work arm measured by the measuring device, the controller comprising:
 an automatic stop function to stop the work arm in a fixed holding pressure measurement posture; and 
 a weight calculation function to estimate the weight of the work arm from the holding pressure measured by the pressure sensor in the fixed holding pressure measurement posture. 
 
 
     
     
       2. The control unit for a work machine as set forth in  claim 1 , wherein the controller converts an operation table showing the characteristics between the manual operation amount and the pilot control pressure of the proportional solenoid valve to an operation table of characteristics according to the weight of the work arm measured by the measuring device. 
     
     
       3. A control unit for a work machine comprising:
 in a work machine where at least a part of a work arm to be operated by a fluid pressure actuator is provided so as to be replaceable, 
 a pilot-operated control valve that controls the fluid pressure actuator; 
 a proportional solenoid valve that pilot-controls the pilot-operated control valve by a pilot control pressure according to an electrical signal corresponding to a manual operation amount; 
 a measuring device that measures a weight of at least a part of the work arm; and 
 a controller converting characteristics between the manual operation amount and the pilot control pressure of the proportional solenoid valve to characteristics according to the weight of the work arm measured by the measuring device, 
 wherein the controller converts an operation table showing the characteristics between the manual operation amount and the pilot control pressure of the proportional solenoid valve to an operation table of characteristics according to the weight of the work arm measured by the measuring device, and 
 
       wherein the controller converts an operation table at a time of attachment of a standard work arm or at a time of attachment of a standard bucket of the proportional solenoid valve to operate the work arm in an antigravity direction to an operation table of characteristics gradually increased so that the pilot control pressure in an intermediate range or less of the manual operation amount is maximized at a rising position of the pilot control pressure. 
     
     
       4. The control unit for a work machine as set forth in  claim 3 , wherein the controller converts the operation table at a time of attachment of a standard work arm or at a time of attachment of a standard bucket of the proportional solenoid valve to operate the work arm in a gravity direction to an operation table of characteristics gradually decreased so as to gradually lower the pilot control pressure in the intermediate range or more of the manual operation amount. 
     
     
       5. A control unit for a work machine comprising:
 in a work machine where at least a part of a work arm to be operated by a fluid pressure actuator is provided so as to be replaceable, 
 a pilot-operated control valve that controls the fluid pressure actuator; 
 a proportional solenoid valve that pilot-controls the pilot-operated control valve by a pilot control pressure according to an electrical signal corresponding to a manual operation amount; 
 a measuring device that measures a weight of at least a part of the work arm; and 
 a controller converting characteristics between the manual operation amount and the pilot control pressure of the proportional solenoid valve to characteristics according to the weight of the work arm measured by the measuring device, 
 wherein the controller converts an operation table showing the characteristics between the manual operation amount and the pilot control pressure of the proportional solenoid valve to an operation table of characteristics according to the weight of the work arm measured by the measuring device, and 
 wherein the controller converts an operation table at a time of attachment of a standard work arm or at a time of attachment of a standard bucket of the proportional solenoid valve to operate the work arm in a gravity direction to an operation table of characteristics gradually decreased so as to gradually lower the pilot control pressure in an intermediate range or more of the manual operation amount.